APOD: Equinox on Planet Earth (2019 Mar 20)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 4474
Joined: Fri Dec 04, 2009 3:27 am

APOD: Equinox on Planet Earth (2019 Mar 20)

Post by APOD Robot » Wed Mar 20, 2019 4:06 am

Image Equinox on Planet Earth

Explanation: Welcome to an equinox on planet Earth. Today is the first day of spring in our fair planet's northern hemisphere, fall in the southern hemisphere, with day and night nearly equal around the globe. At an equinox Earth's terminator, the dividing line between day and night, connects the planet's north and south poles as seen at the start of this remarkable time-lapse video compressing an entire year into twelve seconds. To make it, the Meteosat satellite recorded these infrared images every day at the same local time from a geosynchronous orbit. The video actually starts at the September 2010 equinox with the terminator aligned vertically. As the Earth revolves around the Sun, the terminator tilts to provide less daily sunlight to the northern hemisphere, reaching the solstice and northern hemisphere winter at the maximum tilt. As the year continues, the terminator tilts back again and March 2011 equinox arrives halfway through the video. Then the terminator swings past vertical the other way, reaching the the June 2011 solstice and the beginning of northern summer. The video ends as the September equinox returns.

<< Previous APOD This Day in APOD Next APOD >>

Boomer12k
:---[===] *
Posts: 2691
Joined: Sun Apr 22, 2007 12:07 am

Re: APOD: Equinox on Planet Earth (2019 Mar 20)

Post by Boomer12k » Wed Mar 20, 2019 8:35 am

Bit fast, but I guess that was the point...the sunlight rising and falling on both hemispheres... Cool...

:---[===] *

heehaw

Re: APOD: Equinox on Planet Earth (2019 Mar 20)

Post by heehaw » Wed Mar 20, 2019 9:20 am

These days, time does seem to go by just that fast!

User avatar
orin stepanek
Plutopian
Posts: 6981
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: Equinox on Planet Earth (2019 Mar 20)

Post by orin stepanek » Wed Mar 20, 2019 12:24 pm

Wow! Not liked today by the internet; First time I got a Forbidden sign; then my reply wouldn't post; then a check your internet! Internet on! :roll: Well; anyway, night and day about the same all over! out here ; switching to warmer weather! :D
Orin

Smile today; tomorrow's another day!

Guest

Re: APOD: Equinox on Planet Earth (2019 Mar 20)

Post by Guest » Wed Mar 20, 2019 7:11 pm

could they clean the glass already? :lol2:

that kind of view and the windows are smudged!

dan

Re: APOD: Equinox on Planet Earth (2019 Mar 20)

Post by dan » Thu Mar 21, 2019 1:40 am

It's all relative, but I feel like it would be more informative if the sun's frame of reference was fixed and the Earth tilted in the image (based on confusion of my kids). Cool video nonetheless.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 18555
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Equinox on Planet Earth (2019 Mar 20)

Post by neufer » Thu Mar 21, 2019 5:44 pm

dan wrote:
Thu Mar 21, 2019 1:40 am

It's all relative, but I feel like it would be more informative if the sun's frame of reference was fixed and the Earth tilted in the image (based on confusion of my kids).
Relative to both the Meteosat geostationary satellite and the background star field the Earth axial tilt remains essentially fixed over the year.

Doing what you suggest is not only awkward (using Meteosat data) but would be equally as misleading.
Art Neuendorffer